An ANA test detects antinuclear antibodies (ANA) in your blood. Your immune system normally makes antibodies to help you fight infection. In contrast, antinuclear antibodies often attack your body's own tissues — specifically targeting each cell's nucleus.
In most cases, a positive ANA test indicates that your immune system has launched a misdirected attack on your own tissue — in other words, an autoimmune reaction. But some people have positive ANA tests even when they're healthy.
Your doctor may order an ANA test if he or she suspects you have an autoimmune disease such as lupus, rheumatoid arthritis or scleroderma.
A negative ANA reading means no autoantibodies are present in the body. However, a positive ANA reading alone does not indicate an autoimmune disease. Why?
The positive ANA reading simply tells your doctor to keep looking. In fact, you may have a “false positive” ANA, which means that the evidence is not there to make a diagnosis of lupus or any other autoimmune disease. To make a definite diagnosis, your doctor will need more blood tests along with history of your symptoms and a physical examination.
Please note a positive ANA does not require immediate treatment. Remember, lab levels vary, some autoantibodies are normal and this may be a false positive result. Your doctor will determine what happens next based on additional exploration. By working with your doctor and asking questions you will get the best care for your particular situation.
Keep in mind, even if your ANA reading does lead to an autoimmune diagnosis, there are treatments for autoimmune diseases.
Your rheumatologist will interpret your ANA in the context of other laboratory studies and your clinical history, including family history. Remember a single positive ANA does not imply autoimmune disease.